In Dragon Age 2 it was hard for my mage character to trust anyone since the world didn't want Merrill and her to be independent. Because of this now I am reconsidering my choice about the Rachni Queen in Mass Effect. My pro-Alliance (and somewhat pro-Quarian) isolationist characters have let her free because the Alliance wasn't in war with her, the decision couldn't be undone and alien species would use her death against humans. However, she could be lying about the Rachni Wars, she intends to hide and her minions are hostile without her guidance. Unfortunately there is no third option. The rachni are already building ships and attacking the pirates in Mass Effect 2 ("They were obliterated").